Quick verdict
Clerk for fastest time-to-working-auth. Supabase Auth for ownership and bundled auth + database. Auth0 for enterprise B2B with SSO, SAML, SCIM requirements. Consumer and indie: almost always Clerk or Supabase.
The ownership angle (matters more for AI-built apps)
Founders who generate apps with AI usually want code they own. If your auth provider also owns your user database, you’ve leaked ownership in a subtle place.
- Supabase Auth: users live in your own Postgres
auth.userstable. Full export. Full control. - Clerk: users live in Clerk’s infrastructure. Export is possible but limited (password hashes require special format). Migration is a real project.
- Auth0: similar to Clerk — users in Auth0 tenant. Export and migration tools exist but are not trivial.
For a consumer app that might pivot or get acquired, Supabase Auth gives you the most flexibility.
Head-to-head comparison
| Dimension | Clerk | Supabase | Auth0 |
|---|---|---|---|
| Expo SDK | Official | Official | Official |
| Pre-built UI | Yes | No | Limited |
| Users own-db | No | Yes | No |
| Free tier MAUs | 10k | 50k | 25k |
| SAML / SSO | Enterprise tier | Via config | First-class |
| SCIM provisioning | Enterprise | Not native | Yes |
| Passkeys / WebAuthn | Yes | Beta | Yes |
| Setup time | ~10 min | ~20 min | ~45 min |
| Cost at 100k MAU | $200+ | Free | $1,000+ |
When Clerk wins
- Consumer apps where time-to-first-working-auth matters most.
- Apps that need prebuilt UI components (sign-in, sign-up, user profile) to skip screen design.
- Teams that want passkeys, social login, and organizations with zero server work.
- B2B SaaS where workspaces matter but enterprise SSO doesn’t yet.
When Supabase Auth wins
- You’re already using Supabase as the database — zero extra vendor.
- Code ownership matters; you want users in your own Postgres.
- You want to pair auth with row-level security out of the box.
- Cost-sensitive apps at scale — free MAUs cap is very high.
- Open-source / self-host is a future requirement.
When Auth0 wins
- Selling to enterprise buyers who require SAML, SCIM, or specific IdPs.
- Regulated industries (healthcare, finance) where Auth0’s certifications help.
- Multi-tenant B2B where each tenant may want different identity providers.
- Teams that already have Auth0 institutional knowledge.
The decision framework
- Do buyers demand SAML/SSO? Yes → Auth0. No → continue.
- Are you already using Supabase for data? Yes → Supabase Auth. No → continue.
- Do you want pre-built auth UI and passkeys now? Yes → Clerk. No → Supabase Auth (more flexible, cheaper).
That’s the whole decision tree for the vast majority of apps.
Common mistakes
- Picking Auth0 for an indie consumer app. Overkill, expensive, slower setup.
- Using three vendors (Clerk + Supabase + Auth0) when one would do. Integration complexity compounds.
- Rolling your own auth in 2026. Don’t. Security bugs you never detect.
- Forgetting RLS when pairing Clerk with Supabase. Users can see each other’s data without the JWT template wired.
- Planning to migrate later. Plan not to. Pick carefully up front.